Question

迷住了我对尝试使用Java进行开发是不熟悉的，我正努力创建用户登录页面。

我想检查用户是否有会话，并且是否拥有在身份验证时设置的可用密钥，否则我希望将其转发到 loginPage.jsp

当我不对servlet使用以下映射时，我提供的代码将起作用。

 <servlet-mapping>
   <servlet-name>ControllerServlet</servlet-name>
   <url-pattern>/</url-pattern> -- This works by itself only works on paths not .jsp files
   <url-pattern>*.jsp</url-pattern> -- if i include this i only get blank webpages
  </servlet-mapping>

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_4_0.xsd" id="WebApp_ID" version="4.0">
  <display-name>Project1</display-name>
  <servlet>
    <servlet-name>ControllerServlet</servlet-name>
    <servlet-class>ControlServlet</servlet-class>
  </servlet>
  <servlet-mapping>
   <servlet-name>ControllerServlet</servlet-name>
   <url-pattern>/</url-pattern> //Works when by itself 
   <url-pattern>*.jsp</url-pattern> //breaks when i enabled this 
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.html</welcome-file>
    <welcome-file>index.htm</welcome-file>
    <welcome-file>index.jsp</welcome-file>
    <welcome-file>default.html</welcome-file>
    <welcome-file>default.htm</welcome-file>
    <welcome-file>default.jsp</welcome-file>
  </welcome-file-list>
</web-app>

控制Servlet.java



import java.io.IOException;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
/**
 * Servlet implementation class ControlServlet
 */

public class ControlServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * @see HttpServlet#HttpServlet()
     */
    public ControlServlet() {
        super();
        // TODO Auto-generated constructor stub
    }

    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//      // TODO Auto-generated method stub
        HttpSession session = request.getSession(false);
        if (session == null) {
            // Not created yet. Now do so yourself.
            session = request.getSession();
        } else {
            // Already created.
        }

        //Check if User is Logged in

         String pathInfo = (request.getPathInfo() != null) ? request.getPathInfo() : request.getServletPath();
            System.err.println("check1");
             System.err.println(session.getAttribute("name") == null);
             System.err.println("check2");
             System.err.println(!"/loginPage.jsp".equals(pathInfo));         
         System.err.println(pathInfo);


         if (session.getAttribute("name") == null && !"/loginPage.jsp".equals(pathInfo))
         {   
             RequestDispatcher requestDispatcher = request.getRequestDispatcher("/loginPage.jsp");
             requestDispatcher.forward(request, response);
             //response.sendRedirect("loginPage.jsp");
             System.err.println("did this ever happen?");

         }else {

         }
    }

    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        doGet(request, response);
    }

}

requestDispatcher.forward（）返回空白网页

0 个答案: